This invention relates to laser safety, and in particular to laser beam terminating systems.
One of the safety problems associated with the use of lasers is eye protection. Even a relatively low power laser, say one milliwatt, has such a high energy density that looking directly into the beam can cause permanent retinal damage. Also, even for medium power lasers, say one watt, even the scattered light can be temporarily blinding, and at higher powers can be permanently damaging.
In the typical experimental situation, a laser beam is directed toward some arrangement of other optical elements and after the beam has traversed those elements an appropriate optical terminator is required to eliminate the remaining light. Termination can be particularly important as indicated earlier for higher power systems in order to avoid eye damage, but also, even for low power systems it is often desirable to eliminate the remaining beam so that it does not cause interference effects upstream that could disrupt the experimental setup. At the present time, for low power systems, a simple system such as a card is used as a beam stop, and generally the upstream effects are ignored. For high power systems, more elaborate schemes must be used. For example, one approach is to use a laser power meter as a beam stop. Neither of these approaches is particularly good. For example in the case of the card, scatter can cause effects upstream, and in the high power case using a power meter is indeed an expensive way to proceed.
Clearly what is needed is an inexpensive laser optical terminator that essentially absorbs all or substantially all of the light impinging on it.